title: Transcriptome mining, functional characterization, and phylogeny of a large terpene synthase gene family in spruce (Picea spp.).
abstract: BACKGROUND
  In conifers, terpene synthases (TPSs) of the gymnosperm-specific TPS-d subfamily form a diverse array of mono-, sesqui-, and diterpenoid compounds, which are components of the oleoresin secretions and volatile emissions. These compounds contribute to defence against herbivores and pathogens and perhaps also protect against abiotic stress.
  
  
  RESULTS
  The availability of extensive transcriptome resources in the form of expressed sequence tags (ESTs) and full-length cDNAs in several spruce (Picea) species allowed us to estimate that a conifer genome contains at least 69 unique and transcriptionally active TPS genes. This number is comparable to the number of TPSs found in any of the sequenced and well-annotated angiosperm genomes. We functionally characterized a total of 21 spruce TPSs: 12 from Sitka spruce (P. sitchensis), 5 from white spruce (P. glauca), and 4 from hybrid white spruce (P. glauca × P. engelmannii), which included 15 monoterpene synthases, 4 sesquiterpene synthases, and 2 diterpene synthases.
  
  
  CONCLUSIONS
  The functional diversity of these characterized TPSs parallels the diversity of terpenoids found in the oleoresin and volatile emissions of Sitka spruce and provides a context for understanding this chemical diversity at the molecular and mechanistic levels. The comparative characterization of Sitka spruce and Norway spruce diterpene synthases revealed the natural occurrence of TPS sequence variants between closely related spruce species, confirming a previous prediction from site-directed mutagenesis and modelling.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Keeling
authors.forename: Sabrina
authors.initials: S
authors.lastname: Weisshaar
authors.forename: Steven G
authors.initials: SG
authors.lastname: Ralph
authors.forename: Sharon
authors.initials: S
authors.lastname: Jancsik
authors.forename: Britta
authors.initials: B
authors.lastname: Hamberger
authors.forename: Harpreet K
authors.initials: HK
authors.lastname: Dullat
authors.forename: Jörg
authors.initials: J
authors.lastname: Bohlmann
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D008401:Gas Chromatography-Mass Spectrometry; D020869:Gene Expression Profiling; D008958:Models, Molecular; D005810:Multigene Family; D010802:Phylogeny; D028222:Picea / Q000201:enzymology / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D010940:Plant Proteins; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase